Lubricant oil cooling apparatus for power transmission apparatus

ABSTRACT

A lubricant oil cooling apparatus  1 , which lubricates a speed reducer  10  transmitting and outputting the power of a motor  11 , includes first supporting members  5   b , a bed  5  supporting the motor  11 , and a cooling pipe  4  which penetrates the first supporting members  5   b  while contacting them and constitutes a part of piles supplying the lubricant oil to the speed reducer  10.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority from provisional applications No. 2009-070135 filed on Mar. 23, 2009, the entire disclosure of which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lubricant oil cooling apparatus for a power transmission apparatus.

2. Description of Related Art

Apparatuses for cooling lubricant oil have been publicly known.

For example, an oil cooling engine apparatus disclosed in Japanese Unexamined Patent Publication No. 2002-147234, which is arranged so that lubricant oil lubricating a slide portions of the engine is cooled and then returns to the slide portion again, is characterized in that, a lubricant oil pump is provided in the engine, the engine and auxiliaries such as a carburetor and a muffler are enclosed by a tubular frame and the engine is supported by this frame, the inside of the frame functions as a path through which the lubricant oil passes, and the lubricant oil air-cooled in the frame circulates around the slide portion as the aforesaid path is connected to the lubricant oil pump. Since the lubricant oil flows on the oil path inside the frame, the heat dissipation area is large because the total length of the frame is long, with the result that the heat dissipation by the frame is effective.

Japanese Unexamined Patent Publication No. 2002-147234 is, however, disadvantageous in that the frame as an oil path must be enlarged and/or elongated if the heat dissipation effect is enhanced.

In consideration of the above, an objective of the present invention is to provide a lubricant oil cooling apparatus which improves the heat dissipation effect without enlarging and/or elongating the heat-dissipating oil path, and increases the thermal rating of a power transmission apparatus.

SUMMARY OF THE INVENTION

In the present invention, a lubricant oil cooling apparatus, for a power transmission apparatus transmitting and outputting power of a motor, cools lubricant oil lubricating the power transmission apparatus and includes: a bed which includes a first supporting member and supports the motor; and a cooling pipe which penetrates the first supporting member while contacting the first supporting member and constitutes a part of a pipe which supplies the lubricant oil to the power transmission apparatus.

According to the arrangement above, the cooling pipe constituting a part of the pipe supplying the lubricant oil to the power transmission apparatus penetrates the first supporting member constituting a part of the bed supporting the motor, while contacting the first supporting member. This allows the lubricant oil flowing in the cooling pipe to dissipate heat not only from the surface of the cooling pipe but also from the first supporting member contacting the cooling pipe. Since, the first supporting member of the bed supporting the motor is utilized for heat dissipation of the lubricant oil, it is possible to improve the heat dissipation effect without enlarging and/or elongating the oil path for heat dissipation, and to improve the thermal rating of the power transmission apparatus.

The lubricant oil cooling apparatus of the present invention may be arranged so that the bed includes: a fixing plate which fixes the motor and is supported by the first supporting member in a direction in which the motor is fixed; and a second supporting member which has a surface with which the first supporting member is in contact and supports the fixing plate together with the first supporting member.

According to this arrangement, the bed fixes the motor by the fixing plate and supports, by the first supporting member and the second supporting member, the fixing plate to which the motor is fixed. Furthermore, the second supporting member contacting the cooling pipe also contacts the fixing plate and the second supporting member. This allows the lubricant oil flowing in the cooling pipe to dissipate heat not only from the surface of the cooling pipe and the surface of the first supporting member but also from the fixing plate and the second supporting member contacting the first supporting member, thereby further improving the thermal rating of the power transmission apparatus.

The lubricant oil cooling apparatus of the present invention is arranged to further include a casing which houses the power transmission apparatus along with the lubricant oil, wherein, the cooling pipe is arranged to be lower than a height position of an oil level of the lubricant oil in the casing.

According to the arrangement above, it is possible to prevent air from entering the cooling pipe even if the casing housing the lubricant oil is inclined, because the cooling pipe is positioned to be lower than the height position of the oil level of the lubricant oil in the casing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation of a lubricant oil cooling apparatus.

FIG. 2 is a top view showing the inside of the bed.

FIG. 3 schematically illustrates the lubricant oil cooling apparatus.

FIG. 4 is a top view of the lubricant oil cooling apparatus.

FIG. 5 is a profile of the lubricant oil cooling apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following will describe a lubricant oil cooling apparatus 1 of an embodiment according to the present invention with reference to figures.

As shown in FIG. 1, the lubricant oil cooling apparatus 1 of the present embodiment is a lubricant oil cooling apparatus which cools lubricant oil for lubricating a power transmission apparatus 10 (hereinafter, speed reducer 10) which transmits and outputs the power from the motor 11. This oil cooling apparatus 1 includes a bed 5 including first supporting members 5 b and supports a motor 11 and a cooling pipe 4 which penetrates the first supporting members 5 b while contacting them and constitutes a part of supply pipes 120 which supply lubricant oil to the speed reducer 10.

(Mechanical Structure)

The lubricant oil cooling apparatus 1 cools lubricant oil which lubricates a speed reducer 10 used for a bucket wheel excavator for surface mining. Although not illustrated, the bucket wheel excavator has a bucket wheel in which plural buckets are circumferentially provided at predetermined intervals. As the rotating bucket wheel is forced to contact a mining target, ores or the like are successively mined. The ores or the like which have been successively mined are moved by a belt conveyer or the like on a boom. The bucket wheel is rotated by the power of the motor 11 transmitted by the speed reducer 10.

The speed reducer 10 of the present embodiment is housed in a casing 6 while being dipped in the lubricant oil to reach a predetermined height position in the oil. The speed reducer 10 has an input shaft 10 a to which the power of the motor 11 is input and an output shaft 10 b by which the power is output to the bucket wheel. The speed reducer 10 is housed in the casing 6 so that the input shaft 10 a and the output shaft 10 b rotatably jut out. The speed reducer 10 is supported by the bucket wheel at the output shaft 10 b. The torque to the speed reducer 10 generated because the speed reducer 10 rotates the bucket wheel is countered and restrained by fixing the casing 6 housing the speed reducer 10 to the boom or the like of the belt conveyer.

(Bed 5)

The above-described motor 11 by which the power is input to the speed reducer 10 is, as shown in FIG. 1, supported by the bed 5. The bed 5 supporting the motor 11 is supported so as to be suspended by the casing 6 housing the speed reducer 10. The bed 5 has a fixing plate 5 a, plural first supporting members 5 b, two second supporting members 5 c, and a substrate 5 d.

The fixing plate 5 a is a flat plate member to which the motor 11 is fixed, and constitutes the top surface of the bed 5. The fixing plate 5 a is long in the direction in which the power of the motor 11 is output. The motor 11 is fixed in such a way as to be placed on protruding fixing portions 51 which are close to one end of the fixing plate 5 a in the longitudinal directions. On the other hand, the fixing plate 5 a is connected to the casing 6 by a suspending member 55, at the other end in the longitudinal directions. In this way, the casing 6 supports the bed 5 by a suspending manner.

Hereinafter, a longitudinal direction of the fixing plate 5 a will be referred to as X direction. A direction which is orthogonal to the X direction and in which the motor 11 is fixed to the fixing plate 5 a will be refereed to as Y direction. A direction orthogonal to both the X direction and the Y direction will be referred to as Z direction.

Each of the second supporting members 5 c is shaped like a flat plate. Two second supporting members 5 c are formed so that they oppose each other and equally distanced from a center line of the fixing plate 5 a which line extends in the X direction and equally divides the fixing plate 5 a in two in the Z direction. In other words, as shown in FIG. 2, each second supporting member 5 c is a plate orthogonal to the Z direction and is long in the X direction.

Each of the first supporting members 5 b is shaped like a flat plate. The plural first supporting members 5 b are formed such that flat plates which are in parallel to one another and aligned in the Z direction extend in the Z direction from the two second supporting members 5 c. At least one of the first supporting member 5 b is further provided at its center with a through hole in which the later-described cooling pipe 4 penetrates while contacting the hole.

The substrate 5 d is a flat plate with which the edges of the first supporting members 5 b and the second supporting members 5 c are in contact, and constitutes the bottom surface of the bed 5. This substrate 5 d is long in the direction in which the motor 11 outputs power. In other words, the first supporting members 5 b and the second supporting members 5 c formed on the substrate 5 d support the fixing plate 5 a in the Y direction (i.e. in the direction in which the motor 11 is fixed).

As such, the bed 5 has the second supporting members 5 c through which the cooling pipe 4 allowing the lubricant oil to flow penetrates while contacting the members 5 c. With this, the lubricant oil flowing in the cooling pipe 4 dissipates heat not only from the surface of the cooling pipe 4 but also from the first supporting members 5 b contacting the cooling pipe 4. In this way, since the first supporting members 5 b of the bed 5 supporting the motor 11 are used for dissipating heat of the lubricant oil, the heat dissipation effect is improved without enlarging and/or elongating the oil path for heat dissipation, and the thermal rating of the speed reducer 10 is improved.

In addition to the above, the bed 5 is formed so that each of the second supporting members 5 c contacts the substrate 5 d at one end in the Y direction, contacts the fixing plate 5 a at the other end in the Y direction, and contacts the first supporting members 5 b at one end in the Z direction. Therefore, the heat of the lubricant oil flowing in the cooling pipe 4 is dissipated not only from the surface of the cooling pipe 4 and the surfaces of the first supporting members 5 b but also from the fixing plate 5 a, the second supporting members 5 c, and the substrate 5 d which are in contact with the first supporting members 5 b. This further improves the thermal rating of the speed reducer 10.

It is noted that the contact point between the cooling pipe 4 and each of the first supporting members 5 b is welded to facilitate the heat conduction. Also, the contact points of the fixing plate 5 a, the plural first supporting members 5 b, the two second supporting members 5 c, and the substrate 5 d are welded to facilitate the heat conduction.

(Supply Pipes 120)

As shown in FIG. 3, the supply pipes 120 of the present embodiment supply, by an oil pump 3, the lubricant oil from an oil tank 2 storing the lubricant oil having lubricated the speed reducer 10 to the casing 6 which houses the speed reducer 10. More specifically, the supply pipes 120 include supply pipes 120 a, 120 b, and 120 c and the cooling pipe 4.

The supply pipe 120 a is a tubular member which connects the oil tank 2 with a suction port 3 b of the oil pump 3 by which the lubricant oil is sucked. More specifically, one end of the supply pipe 120 a is connected to a side face of the oil tank 2 neighboring the bed 5 in the Z direction, the side face extending in the X direction. The supply pipe 120 a curvedly connects the oil tank 2 with the suction port 3 b of the casing 6 which is above the oil tank 2 in the Y direction (see FIG. 4 and FIG. 5).

The oil pump 3 is connected to the rotation axis of the speed reducer 10, so that the lubricant oil is sucked and discharged in response to the rotation of the rotation axis. Alternatively, the oil pump 3 may be driven by an additionally-provided motor or the like.

The supply pipe 120 b is a tubular member connecting an outlet 3 c of the oil pump 3, from which the lubricant oil is discharged, with the cooling pipe 4. More specifically, one end of the supply pipe 120 b is connected to the outlet 3 c. The supply pipe 120 b curvedly connects the outlet 3 c with an end of the cooling pipe 4 which is below the outlet 3 c in the Y direction (see FIG. 1 and FIG. 4). It is noted that the cooling pipe 4 which constitutes a part of the supply pipes 120 will be discussed later.

The supply pipe 120 c is a tubular member connecting the cooling pipe 4 with the casing 6. More specifically, one end of the supply pipe 120 c is connected to the other end of the cooling pipe 4. The supply pipe 120 c is provided from the cooling pipe 4 c to a supply port 6 a formed in the upper part of the casing 6 in the Y direction (see FIG. 4 and FIG. 5).

(Cooling Pipe 4)

Now, the cooling pipe 4 constituting a part of the supply pipes 120 will be described. As shown in FIG. 2, the cooling pipe 4 includes cooling pipes 4 a, 4 b, and 4 c and forms a U-shape. The cooling pipe 4 connects the supply pipe 120 b with the supply pipe 120 c.

The cooling pipe 4 a is a straight tubular member and penetrates the through holes of plural first supporting members 5 b formed on one end side of the bed 5 in the Z direction, while contacting the holes. The cooling pipe 4 a is welded with the first supporting member 5 b at the contact point therebetween. The cooling pipe 4 a has a flange at is one opening, and this flange is connected to the supply pipe 120 b. The cooling pipe 4 a has another flange at the other opening. The cooling pipe 4 a is connected to the cooling pipe 4 b such that the flange is fixed to a flange formed at an opening of the cooling pipe 4 b.

The cooling pipe 4 b is a tubular member which is U-shaped when viewed in the Y direction, and penetrates the through holes of a pair of second supporting members 5 c while contacting the holes. The cooling pipe 4 b is welded with the second supporting member 5 c at the contact point therebetween. The cooling pipe 4 b is connected to the cooling pipe 4 c such that a flange formed at the other opening of the pipe 4 b is fixed to a flange formed at an opening of the cooling pipe 4 c.

The cooling pipe 4 c is a straight tubular member, and penetrates the through holes of at least one first supporting member 5 b on the other end side of the bed 5 in the Z direction, while contacting the holes. The cooling pipe 4 c is welded with the first supporting member 5 b at the contact point therebetween. The cooling pipe 4 c has a flange at the other opening thereof, and this flange is connected to the supply pipe 120 c.

The height position of the cooling pipe 4 will be described. The speed reducer 10 of the present embodiment is used for a bucket wheel excavator as described above. Since the bucket wheel which is rotatably supported by the speed reducer 10 excavates the excavation target, the bucket wheel excavator allows the bucket wheel to incline up to a predetermined angle (15 degrees in the present embodiment). More specifically, the speed reducer 10 side of the bed 5 in the longitudinal direction is allowed to incline downward.

The cooling pipe 4 is disposed to be lower than the oil level of the lubricant oil in the casing 6 when the speed reducer 10 is maximally inclined. In other words, the cooling pipe 4 is provided vertically below the oil level of the lubricant oil in the casing 6 when the speed reducer 10 is maximally inclined. This arrangement prevents air in the casing 6 from entering the cooling pipe 4 even when the speed reducer 10 is inclined at a predetermined angle due to the incline of the bucket wheel at a predetermined angle.

(Communication Tube 121)

As shown in FIG. 3, a communication tube 121 is provided to discharge the lubricant oil from the casing 6 which houses the speed reducer 10 to the oil tank 2.

More specifically, the communication tube 121 has a communication tube 121 a and a communication tube 121 b. As shown in FIG. 5, the communication tube 121 a connects, with the oil tank 2, an exhaust port 6 b formed in a part of the casing 6 which part is a central part in the Z direction and is a lower part in the Y direction. The communication tube 121 a has a larger diameter than the cooling pipe 4. The communication tube 121 a is arranged so that the lubricant oil inside the casing 6 moves to the oil tank 2 by its own weight.

The communication tube 121 b connects, with the oil tank 2, a connection port 6 c which is formed in a part of the casing 6 which part is an edge part in the Z direction and is a lower part in the Y direction. The communication tube 121 b causes air in the oil tank 2 to move to the casing 6.

(Movement)

The following will describe the movement of the lubricant oil regarding the lubricant oil cooling apparatus 1 of the present embodiment.

First, the lubricant oil having lubricated the speed reducer 10 in the casing 6 moves from the exhaust port 6 b to the oil tank 2 via the communication tube 121 a by its own weight. The air trapped in the oil tank 2 is moved to the casing 6 via the communication tube 121 b.

Subsequently, the lubricant oil stored in the oil tank 2 is pumped by the oil pump 3 via the supply pipe 120 a. More specifically, the lubricant oil stored in the oil tank 2 is sucked into the suction port 3 b via the supply pipe 120 a, by the oil pump 3 which is driven by the rotation axis of the speed reducer 10. Thereafter, the lubricant oil pumped by the oil pump 3 is discharged from the outlet 3 c by the oil pump 3, and supplied to the cooling pipe 4 of the bed 5 via the supply pipe 120 b.

Then the lubricant oil supplied to the cooling pipe 4 passes through the cooling pipes 4 a, 4 b, and 4 c in this order. The lubricant oil flowing in the cooling pipe 4 dissipates heat to the outside via the outer surface of the cooling pipe 4 and the first supporting members 5 b, because the cooling pipe 4 penetrates the first supporting members 5 b while contacting them.

In addition to the above, since the first supporting members 5 b also contact the fixing plate 5 a, the second supporting members 5 c, and the substrate 5 d, the lubricant oil flowing in the cooling pipe 4 dissipates heat also from the fixing plate 5 a, the second supporting members 5 c, and the substrate 5 d via the first supporting members 5 b. In other words, the fixing plate 5 a, the first supporting members 5 b, the second supporting members 5 c, and the substrate 5 d function not only supporters of the motor 11 but also radiation fins for heat dissipation of the lubricant oil flowing in the cooling pipe 4.

Thereafter, the lubricant oil flowing in the cooling pipe 4 is supplied to the supply port 6 a via the supply pipe 120 c, as the oil in the cooling pipe 4 is pushed by the lubricant oil discharged from the oil pump 3. In other words, the lubricant oil flowing in the cooling pipe 4 is supplied to the casing 6 via the supply pipe 120 c so as to lubricate the speed reducer 10.

Outline of Present Embodiment

A lubricant oil cooling apparatus 1 of the present embodiment is a lubricant oil cooling apparatus for cooling lubricant oil which lubricates a power transmission apparatus 10 (speed reducer 10) which transmits and outputs the power of a motor 11, and includes first supporting members 5 b, a bed 5 supporting the motor 11, and a cooling pipe 4 which penetrates the first supporting members 5 b while contacting them and constitutes a part of pipes which supplies the lubricant oil to the speed reducer 10.

According to the arrangement above, the cooling pipe 4 constituting a part of the pipes supplying the lubricant oil to the speed reducer 10 penetrates the first supporting members 5 b constituting parts of the bed 5 supporting the motor 11 while contacting the members 5 b. This allows the lubricant oil flowing in the cooling pipe 4 to dissipate heat not only from the surface of the cooling pipe 4 but also from the first supporting members 5 b contacting the cooling pipe 4. Since the first supporting members 5 b of the bed 5 supporting the motor 11 are used for dissipating the heat of the lubricant oil, the heat dissipation effect is improved without enlarging and/or elongating the oil path for heat dissipation, and the thermal rating of the power transmission apparatus is improved.

The bed 5 of the lubricant oil cooling apparatus 1 of the present embodiment may be arranged to include: a fixing plate 5 a which fixes the motor 11 and is supported by the first supporting members 5 b in the direction in which the motor 11 is fixed; and second supporting members 5 c each of which has a flat surface with which the first supporting members 5 b are in contact and supports the fixing plate 5 a together with the first supporting members 5 b.

According to the arrangement above, the bed 5 fixes the motor 11 by the fixing plate 5 a and supports, by the first supporting members 5 b and the second supporting members 5 c, the fixing plate 5 a which fixes the motor 11. Furthermore, the second supporting members 5 c contacting the cooling pipe 4 also contact the fixing plate 5 a and the second supporting members 5 c. With this, the lubricant oil flowing in th cooling pipe 4 dissipates heat not only from the surface of the cooling pipe 4 and the surfaces of the first supporting members 5 b but also from the fixing plate 5 a and the second supporting members 5 c contacting the first supporting members 5 b. This further improves the thermal rating of the speed reducer 10.

The lubricant oil cooling apparatus 1 of the present embodiment further includes a casing 6 which houses the speed reducer 10 along with the lubricant oil, and the cooling pipe 4 is provided to be lower than the height position of the oil level of the lubricant oil in the casing 6.

According to the arrangement above, even when the casing 6 housing the lubricant oil therein is inclined, no air enters into the cooling pipe 4 because this cooling pipe 4 is provided below the height position of the oil level of the lubricant oil in the casing 6.

Variations of Present Embodiment

While the present invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiment of the invention as set forth above is intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims.

In addition to the above, the lubricant oil cooling apparatus 1 of the power transmission apparatus of the present embodiment may alternatively or additionally have the following features.

In the present embodiment, the lubricant oil cooling apparatus 1 is used for bucket wheel excavators: however, the apparatus may be variously used for other purposes, e.g. other excavators such as tunnel boring machines.

In the present embodiment, a power transmission device housed in the casing 6 and lubricated by the lubricant oil is the speed reducer 10: however, the power transmission device may only have a function to change the direction of the rotation axis or may be a device such as a clutch.

In the present embodiment, the cooling pipe 4 is arranged so that all paths are provided in the bed 5: however, the paths of the cooling pipe 4 are not necessarily disposed in this manner as long as at least one of the paths of the cooling pipe 4 is disposed in the bed 5.

In the present embodiment, the motor 11 is supported by the bed 5 and the bed 5 is supported by the casing 6: however, the components are not necessarily supported in this way as long as the bed 5 supports the motor 11. For example, the bed 5 may support both the motor 11 and the casing 6. Alternatively, the bed 5 may be supported by the power transmission apparatus, or the bed may support the power transmission apparatus. (The bed 5 may be inclined or rotatably provided in the air or may be provided on the land.)

The bed 5 is not limited to the arrangement described in the embodiment above and may be differently arranged as long as it has first supporting members 5 b through which the cooling pipe 4 penetrates while contacting the members 5 b. For example, the substrate 5 d is not formed so that the cooling pipe 4 is exposed to the outside air.

The present invention is applicable for any types of lubricant oil cooling apparatuses. 

1. A lubricant oil cooling apparatus for a power transmission apparatus transmitting and outputting power of a motor, the lubricant oil cooling lubricant oil lubricating the power transmission apparatus and comprising: a bed which includes a first supporting member and supports the motor; and a cooling pipe which penetrates the first supporting member while contacting the first supporting member and constitutes a part of a pipe which supplies the lubricant oil to the power transmission apparatus.
 2. The lubricant oil cooling apparatus according to claim 1, wherein, the bed includes: a fixing plate which fixes the motor and is supported by the first supporting member in a direction in which the motor is fixed; and a second supporting member which has a surface with which the first supporting member is in contact and supports the fixing plate together with the first supporting member.
 3. The lubricant oil cooling apparatus according to claim 1, further comprising a casing which houses the power transmission apparatus along with the lubricant oil, wherein, the cooling pipe is arranged to be lower than a height position of an oil level of the lubricant oil in the casing.
 4. The lubricant oil cooling apparatus according to claim 2, further comprising a casing which houses the power transmission apparatus along with the lubricant oil, wherein, the cooling pipe is arranged to be lower than a height position of an oil level of the lubricant oil in the casing. 